1. Field of the Invention
Aspects of the invention relate to digital broadcast transmission and reception apparatuses and methods thereof, and more particularly, to digital broadcast transmission and reception apparatuses to enhance transmission efficiency using residual bytes, and methods thereof.
2. Description of the Related Art
As electronics and communication technologies have progressed, various standards have been developed for use in digital broadcasting, such as the Advanced Television Systems Committee Vestigial Sideband (ATSC VSB) standard in the United States, and the Digital Video Broadcasting-Terrestrial (DVB-T) standard in Europe.
The ATSC VSB standard is used in the National Television System Committee (NTSC) frequency band, and has advantages such as the ease of implementation of a transmitter and a receiver, and in the economic aspect. The ATSC VSB standard uses a single-carrier amplitude modulation Vestigial Sideband (VSB) method, and can transmit high-quality video, audio, and ancilliary data in a single 6-MHz frequency band. Ancilliary data includes control data, conditional access control data, and data associates with program video and audio services, such as closed captioning, and can also refer to independent program services.
FIG. 1 shows the structure of a data frame of the ATSC VSB transmission method according to the related art, and FIG. 2 shows a field of the data frame of FIG. 1 containing residual bytes. As shown in FIG. 1, a single data frame used in the ATSC VSB transmission method consists of two fields. Each field includes a single field sync signal segment, and 312 data segments. A single segment in such a data frame corresponds to a single MPEG-2 packet, and the segment includes a segment sync signal of 4 symbols (1 byte) and 828 data symbols (207 bytes).
The field sync signal and the segment sync signal are used for synchronization and equalization in a broadcast receiver. The field sync signal and the segment sync signal are predetermined data that are known to both a digital broadcast transmitter and a digital broadcast receiver, and are used as reference signals for performing equalization in the receiver.
When each of the 312 data segments of a field of the data frame shown in FIG. 1 is generated, a Reed-Solomon (RS) encoder in the digital broadcast transmitter performs forward error correction (FEC) encoding of 187 data bytes to obtain 20 parity bytes that are appended to the 187 data bytes to obtain the 207 bytes (828 symbols) of the data segment.
Referring to FIG. 2, in the ATSC VSB system according to the related art, the digital broadcast transmitter and the digital broadcast receiver operate on the presumption that a start point of a first data 20 appearing after a field sync signal 10 is a start point of new data 20. However, depending on the size of the data 20, there may be residual bytes 30 at the end of a field that are too small to contain new data. Accordingly, the residual bytes 30 shown in FIG. 2 cannot be used to transmit new data because they would contain only an initial portion of the new data, such that the first data 20 after the field sync signal 10 of the next field would contain a final portion of the new data packet. Thus, a start point of the first data 20 after the field sync signal 10 of the next field would not be the start point of new data as would be expected by the digital broadcast receiver. Accordingly, in the ATSC VSB system according to the related art, the residual bytes 30 are transmitted in an empty state by the digital broadcast transmitter, thereby reducing a transmission efficiency.
Since the residual bytes 30 are transmitted in an empty state by the digital broadcast transmitter of the ATSC VSB system according to the related art, a predetermined number of the data 20 in a field are decoded in the digital broadcast receiver of the ATSC VSB system according to the related art, and the residual bytes 30 are discarded, thereby reducing the transmission efficiency.